Importing a SVG file creates too many faces
The SVG importer likely generates a 2D curve initially, so in future you might be better off to avoid converting to a Mesh first. Some steps below can be skipped if you do that.

Like this:



There's a few ways to do this, the simplest might be to simply ignore the fact that you have a lot of faces, and convert straight into 2D Curve




Convert the Mesh in Object mode to Curve using alt+C. 
Set to 2D Curve type.

Use the Geometry panel to adjust offset / extrude and bevel depth. The Curve object has a lot of the same features as the Font Object type.